The present invention relates to an input device, a display device, and electronic device, and in particular to an input device of a capacitance type, and a display device and electronic device which are provided with such an input device.
In recent years, technique of attaching an input device which is called “touch panel” or “touch sensor” to a display surface side of a display device, and when an input action has been performed by bringing an input tool such as a finger of a user or a touch pen into contact with the touch panel, an input position is detected to be outputted. Since display devices having such a touch panel do not require an input device such as a keyboard, a mouse, or a keypad, they are widely used in portable information terminals such as a mobile phone in addition to computers.
As one of detecting systems for detecting a contact position at which a finger of a user or the like has comes into contact with a touch panel, there is an electrostatic capacitance system. In a touch panel using the capacitance type, a plurality of capacitive elements composed of a pair of electrodes disposed to face each other via a dielectric layer, namely, a driving electrode and a detecting electrode, is provided in plane of the touch panel. When an input action has been performed by bringing such an input tool as a finger of a user or a touch pen into contact with a capacitive element, a capacitance is added to the capacitive element, so that a detected capacitance is changed, which is utilized to detect the input position.
In Japanese Patent Application Laid-Open Publication No. 2012-73783 (Patent Document 1), there is described a display device of a so-called “in-cell type” where a liquid crystal display device composed of liquid crystal display elements and a touch-detecting device of a capacitance type are integrated with each other. Further, in the Patent Document 1, there is such a description that common electrodes for display which are also used as driving electrodes of the touch-detecting device are arranged side by side extending in one direction, while detecting electrodes of the touch-detecting device are arranged side by side so as to extend in a direction intersecting with the common electrodes.
In Japanese Patent Application Laid-Open Publication No. 2012-43298 (Patent Document 2), there is described a technique where in an input device, a plurality of lower transparent electrodes extending in a first direction are arranged in a second direction orthogonal to the first direction, and a plurality of upper transparent electrodes extending in the second direction are arranged in the first direction.
In Japanese Patent Application Laid-Open Publication No. 2012-14329 (Patent Document 3), there is described a technique of detecting an input position in an input device according to a self-capacitance system where the number of electrodes used for sensing is one. Further, in the Patent Document 3, there is a description that the electrode used for sensing has an isosceles trapezoid having an upper side, a lower side and two oblique sides.